Throughout history, open fires have been used to generate heat for a warmer, more comfortable environment, for cooking, and as a source of light for illumination. Fires are also deemed to be aesthetically pleasing, and are frequently made at parties, celebrations, and other social gatherings even though they are not needed for heat, light or cooking. On the other hand, open fires are commonly used in the typical way during camping trips to provide warmth and light as well as a heat source for cooking.
Over the centuries there have been many innovations which made the use of fire safer, more efficient for a particular purpose, and more convenient. The Swedish fire torch is said to have been developed for use by Swedish soldiers during the thirty year war between 1618 and 1648. Through a specially developed sawing process the Swedish soldiers were said to use fresh pinewood as a source of heat and did not need to travel great distances for firewood at camp. The Swedish torch is burnt vertically and burns evenly over a relatively long period of time.
Today, the Swedish torch, also known as a Canadian Candle, is popular because it is a convenient way to start a fire with only one log, provides a flat cooking surface and is self-feeding (it can burn for several hours without any attention). The Swedish torch is easy to build, takes up a small amount of space and is also a good fire to make in snow, as the main part of the construction is kept off the wet ground. The Swedish torch is made by splitting a log into four quarters. The log is then reassembled, leaving equally sized gaps between each of the four pieces. The kindling for the fire is made of smaller pieces of wood which are placed at alternating angles, in a crisscross fashion, in the gaps between the four pieces of the log. The tinder which is used to start the fire is typically placed at the top of the torch and is generally also placed intermittently between the kindling. The burning kindling will drop down into the lower layers of the Swedish torch causing it to ignite all four quarters of the split. Air is able to circulate within the burning log by virtue of the gaps between the split log which, of course, provides oxygen to the burning fire. It is easy to set such a Swedish torch on fire and it will burn freely requiring virtually no additional attention for up to several hours.
In more recent times, numerous devices have been developed which allow people to enjoy open fires for heat, cooking, and simply for the aesthetically pleasing atmosphere which they create. For example, sophisticated charcoal grills have been developed for cooking food over burning wood or charcoal. Various types of liquid hydrocarbon burning torches have been developed for illumination and to provide the desired atmosphere. Logs which are designed for easy lighting and which require little attention and work, such as Duraflame® logs, have also become popular in recent times. Such manufactured logs are typically made with blends of sawdust or agricultural biomass with natural waxes and oils derived from organic materials.
U.S. Pat. No. 8,597,381 describes a fire log which has one or several longitudinal incisions, which penetrate the log but do not reach the side surface and intersect in the log's midsection. A lower part of this log has at least one air duct from the side surface to the log's midsection in case the log is set on a surface which obstructs airflow to the log's lower part. The log's midsection contains an ignition device, which can be an ignition strip, tablet, briquette or other that has been permeated with an ecologically friendly flammable substance that burns fast and evenly.
U.S. Pat. No. 5,833,353 discloses a combustible device which can be ignited to furnish warmth for comfort, heat for cooking, and light for illumination, and which may also be aesthetically pleasing. This device includes a shell formed of combustible material, which defines an updraft chamber, an intake chamber located at the lower portion of the updraft chamber and being in fluid communication with both the updraft chamber and the outside of the shell, and one or more exhaust flues located at the top of the updraft chamber. The flues also are in fluid communication with both the updraft chamber and the outside of the shell, to provide an exit for smoke and ashes formed by combustion in the updraft chamber. The updraft chamber of this device may be tapered, so that the upper portion of the updraft chamber is narrower than the lower portion of the updraft chamber. Preferably, the combustible shell is formed with an aesthetically pleasing appearance, such as a relief shaped like a face. The shell may also include a thick, solid spine along its length, to maintain the balance of the shell while it burns.